#define TRUE 1
#define FALSE 0
#define INVALID -1
#define NULL 0
#define total_instruction 320
#define total_vp 32
#define clear_period 50

typedef struct
{
	int pn;
	int pfn;
	int counter;
	int time;
} pl_type;

pl_type pl[total_vp];

typedef struct pfc_struct
{
	int pn;
	int pfn;
	struct pfc_struct *next;
} pfc_type;

pfc_type pfc[total_vp], *freepf_head, *busypf_head, *busypf_tail;
int diseffect, a[total_instruction];
int page[total_instruction], offset[total_instruction];
int initialize(int);
int FIFO(int);
int LRU(int);
int LFU(int);
int NUR(int);
int OPT(int);

int main()
{
	int s, i, j;
	srand(10 * getpid());
	s = (float)319 * rand() / 32767 / 32767 / 2 + 1;
	for (i = 0; i < total_instruction; i += 4)
	{
		if (s < 0 || s > 319)
		{
			printf("When i==%d,Error,s==%d\n", i, s);
			exit(0);
		}
		a[i] = s;
		a[i + 1] = a[i] + 1;
		a[i + 2] = (float)a[i] * rand() / 32767 / 32767 / 2;
		a[i + 3] = a[i + 2] + 1;
		s = (float)(318 - a[i + 2]) * rand() / 32767 / 32767 / 2 + a[i + 2] + 2;
		if ((a[i + 2] > 318) || (s > 319))
			printf("a[%d+2],a number which is :%d and s==%d\n", i, a[i + 2], s);
	}
	for (i = 0; i < total_instruction; i++)
	{
		page[i] = a[i] / 10;
		offset[i] = a[i] % 10;
	}
	for (i = 4; i <= 32; i++)
	{
		printf("---%2d page frames ---\n", i);
		NUR(i);
	}
	return 0;
}

int initialize(int total_pf)
{
	int i;
	diseffect = 0;
	for (i = 0; i < total_vp; i++)
	{
		pl[i].pfn = INVALID;
		pl[i].counter = 0;
		pl[i].time = -1;
	}
	for (i = 0; i < total_pf - 1; i++)
	{
		pfc[i].next = &pfc[i + 1];
		pfc[i].pfn = i;
	}
	pfc[total_pf - 1].next = NULL;
	pfc[total_pf - 1].pfn = total_pf - 1;
	freepf_head = &pfc[0];
	return 0;
}

int NUR(int total_pf)
{
	int i, j, dp, cont_flag, old_dp;
	pfc_type *t;
	initialize(total_pf);
	dp = 0;
	for (i = 0; i < total_instruction; i++)
	{
		if (pl[page[i]].pfn == INVALID)
		{
			diseffect++;
			if (freepf_head == NULL)
			{
				cont_flag = TRUE;
				old_dp = dp;
				while (cont_flag)
				{
					if (pl[dp].counter == 0 && pl[dp].pfn != INVALID)
					{
						cont_flag = FALSE;
					}
					else
					{
						dp++;
						if (dp == total_vp)
							dp = 0;
						if (dp == old_dp)
							for (j = 0; j < total_vp; j++)
								pl[j].counter = 0;
					}
				}
				freepf_head = &pfc[pl[dp].pfn];
				pl[dp].pfn = INVALID;
				freepf_head->next = NULL;
			}
			pl[page[i]].pfn = freepf_head->pfn;
			freepf_head->pn = page[i];
			freepf_head = freepf_head->next;
		}
		else
			pl[page[i]].counter = 1;
		if (i % clear_period == 0)
			for (j = 0; j < total_vp; j++)
				pl[j].counter = 0;
	}

	printf("NUR:%6.4f\n", 1 - (float)diseffect / 320);
	return 0;
}
